1. Field of the Invention
The present invention relates to a signal processing apparatus, a signal processing method, and a program. More particularly, the invention relates to a signal processing apparatus, a signal processing method, and a program for detecting layer features in flexible and efficient fashion.
2. Description of the Related Art
Recent years have witnessed widespread use of recording devices typified by hard disk recorders. The ever-increasing capacity and highly developed data compression techniques of the hard disk recorder are likely to entail an ever-increasing number of contents that can be recorded on the recording device.
Concomitant with these developments, a growing need is expected for efficiently managing and viewing large quantities of contents held on the recording device. A number of techniques for meeting the need have been proposed so far.
One such technique involves detecting features from a given content by analyzing its video and audio signals so that chapters of the content may be created automatically and only the scenes typical of the detected features may be reproduced continuously in so-called digest reproduction. The user can reproduce the content of interest starting from a desired scene by designating any one of the chapters automatically created by the recording device, or can check the entire content in a short time through digest reproduction.
In creating such chapters of a given content or in carrying out its digest reproduction, the recording device takes into consideration a plurality of features such as the positions of CM's (commercial messages) in the content, the presence or absence of scenes showing people's faces, and the presence or absence of scenes depicting highlights.
The features such as the positions of CM's in the content, the presence or absence of scenes showing people's faces, and the presence or absence of scenes depicting highlights are in turn determined in consideration of another set of multiple features. The latter features may include the positions of scene changes in the content, fade-in and fade-out positions, and the presence or absence of scenes showing people talking.
Furthermore, the features such as the positions of scene changes in the content, fade-in and fade-out positions, and the presence or absence of scenes showing people talking, which are considered to determine the features such as the positions of CM's in the content, the presence or absence of scenes showing people's faces, and the presence or absence of scenes depicting highlights, are determined in consideration of yet another set of multiple features. These features may include the brightness and color of the video signal, power levels of the audio signal, and frequencies in the content of interest.
That is, the ultimate objective of creating chapters and permitting digest reproduction is accomplished through the layered processes for detecting features. Low-level features such as the brightness and color of the video signal, power levels of the audio signal, and frequencies in the content of interest are first detected. High-level features such as the positions of CM's in the content, the presence or absence of scenes showing people's faces, and the presence or absence of scenes depicting highlights are then detected.
Japanese Patent Laid-open No. 2004-282318 discloses illustratively a technique for creating histograms showing the elements making up images and for detecting scene changes based on the histograms thus created.